Truss eor iron bridges



UNITED STATES PATENT OFFICE.

GEORGE W. THAYER, OF SPRINGFIELD, MASSACHUSETTS.

TRUSS FOR IRON BRIDGES.

Specification of Letters Patent No. 10,765, dated April 11, 1854'.

Tall whom t may concern:

Be it known that I, GEORGE W. THAYER, of Springfield, in the county of Hampden and State of Massachusetts, have invented a new and useful Truss forIron Bridges and for Roofs, and I do hereby declare that the following is intended to be a full and exact description thereof, reference being had to the accompanying drawings and to the letters and figures of reference marked thereon.

Figure l represents a perspective view of the truss as applied to a roof or a bridge, Fig. 2 and Fig. 3 represent two of the gothic arch braces detached fromthe truss. Fig. 4- and Fig.` 5 represent portions of the lower cords of the truss. Fig. 6 and Fig. 7 represent portions of the upper cords of the truss. Fig. 8 represents two of the vertical rods wit-h their straining blocks their nuts and screws the longer one extending from the bottom of the lower cords to the top `of the gothic arch braces and the shorter one cords are fastened to the braces.

Each two of the gothic arch braces Fig.

2 and Fig. 3 are locked together at K and L and secured by one of the bolts represent ed at Fig. 9, the lower cords Fig. 4 and Fig. 5 are applied to the tenons and shoulders P P P P at the bottom of the gothic arch braces one on each side and secured thereto by the bolts represented at Fig. 9. The upper cords Fig. 6 and Fig. 7 are applied to the daps and shoulders C C and D D near the middle of the braces and are secured thereto by thebolts represented at Fig. 9. The longer rods one of which is represented at Fig. 8 pass through straining blocks as E seen at Fig. 8 beneath the lower cords or through straining beams beneath the lower cords and running across the bridge, and extend upward between the cords and through the top of the gothic arch braces where they are secured by nuts and screws. The shorter rods one of which is seen at Fig. S pass through straining blocks as F seen at Fig. 8 beneath the lower cords and extend upward between the cords and are secured at the top of the upper cords by straining blocks, nuts and screws.

The advantages of this truss over those of a different construct-ion are first it is not so much affected by the expansion of heat or the contraction of cold; second, it is not increased in length by cambering; third, there is no thrust strain on the cords, but the greater the pressure on the truss is, the nearer the parts are brought together and the closer the joints become; fourth, every piece supports a partof the whole structure, and there is no dead weight of iron or useless material, all these advantages combined renders it more substantial than other structures of the kind now in use.

Having set forth my invention I shall claim- The combining or arranging together as described a series of interlocking and overlapping metallic arched beams, a series ofvertical suspension tie bolts extending from the lower cords to the crowns of the arches of the metallic arched beams and a series of struts or tie bolts, extending from the lower to the upper set of cords, the whole when combined and arranged substantially as set forth, constituting a truss having great strength and advantages as stated and made with one long arched beam to extend over and embrace two or more of the arches.

In testimony whereof I have hereunto set Y my signature this fifteenth day of July, one thousand eight hundred and fifty three.

GEORGE WV. THAYER. 

